The U.S. Justice Department's internal legal opinions are not final agency action and have no force of law, the government asserted in a new Boston federal appeals case confronting the reach of memos that provide regulatory and enforcement guidance to the executive branch.

Opinions from the Office of Legal Counsel have attracted widespread attention in the Trump administration, as Justice Department officials have issued memos arguing why certain high-level officials cannot speak with House Democrats and also why the president's tax returns cannot be released to congressional investigators.

The Justice Department's policy against indicting a sitting president was established by OLC, whose opinion on that matter was cited by Robert Mueller III, the special counsel, in his report on Russia's interference in the 2016 presidential election and President Donald Trump's efforts to impede prosecutors' inquiry. No federal judge has ruled on that policy, but it has been questioned in court.